30 The European Elm Scale 



spraying experiments, scalecide 



(With Atomizer in the Open Air) 



10 Per Cent Solution. One Part Scaleeide With Nine Parts of Water. 



Material — (1). Colonies of hibernating larvae surrounded dead 

 females on a green and healthy quarter-inch twig. (2). Scattered 

 clusters of hibernating larvae on a healthy limb well up in a tree. 

 Some of these larvae are partially concealed in cracks, others fully 

 exposed to the action of the insecticide. (3). Three irregular rows 

 of hibernating larvae apparently in a healthy condition in cracks in 

 the bark of a badly infested American Elm, the bark surrounding the 

 larvae is partly dead. 



Conditions — A clear and sunny afternoon, 2 P. M. Tempera- 

 ture, 42 degrees. 



Application — The insecticide was applied with an atomizer of a 

 usual pattern, whose misty spray wet the bark until the solution stood 

 in the cracks and ran along the bark in drops like milk. 



RESULTS 



Test Foe Death — The same tests were applied as in the experi- 

 ments with kerosene emulsion. 



Results of Counts — Of 1283 larvae examined, only four were 

 living, giving a percentage of efficiency of 99.7 per cent.' This should 

 be total, for the four living ones were sluggish and discolored and 

 would in all probability have died soon. 

 Scaleeide, 1 in 15. One Part Scaleeide With Fourteen Parts of Water. 



Material, conditions, application and tests for death were of the 

 same character as with the 1 in 10 solution. 



Results — Out of 1359 larvae counted, 145 were living, giving evi- 

 dence of life by moving legs or antennae when the test for death was 

 applied. Most of them remained under observation for several min- 

 utes. In some instances the motion was very slight and the larvae 

 appeared to be in a dying condition. To the naked eye they seemed 

 to be of wholly normal appearance, though perhaps a little shrunken. 

 The count probably errs by stating too small a proportion of dead; 

 for there is much to indicate that some few at least were washed away 

 by rains after the branch was sprayed. On the whole the larvae 

 were in such situations on the bark that they were fairly exposed to 

 the spray. Many of those which escaped were concealed in the deeper 

 crevices. The percentage of efficiency with the one in fifteen solution 

 was nearly ninety per cent. 



Scaleeide is manufactured by tlie B. G. Pratt Co., No. 11 Broaaway, New York. 



